Within most industrialized nations, substantial effort is expended in regulating and controlling vehicular traffic. One particularly important species of traffic control device is that which is used to control the passage of vehicles through intersecting portions of streets or roads.
In the United States of America for example, the most common traffic control device used at intersections of streets or roads is typically referred to as “traffic light”, ‘stop light”, or “traffic signal”. Such devices generally utilize one or more illuminatable signals or lights. Perhaps the most common device provides a red light (indicating an instruction to stop), a green light (indicating an instruction to proceed) and an amber light (indicating a transition from green to red).
A number of devices may be used for the light or signally portion of such control devices, one of the most well known and pervasive light or signal structures is provided by a simple reflector and color light filter or lens assembly having one or more incandescent lamps within the assembly interior. A newly emerging type of light or signal structure utilizes a lens assembly illuminated by a plurality of light emitting diodes to transmit light through the lens. The lens may be tinted to provide signal light color. Alternatively, a plurality of appropriately colored light emitting diodes may be selected to yield the desired light color.
Another important traffic control need arises in the regulation of vehicle speed. To maintain safe vehicle travel over streets, roads and the like, the maximum permissible speed for vehicles is usually posted along the roadside. Generally, a plurality of “speed limit” signs are provided at convenient positions along streets or roads and are positioned to be readily observable from vehicles passing thereby. While this system of posting speed limits along roadsides functions well for the most part, several limitations in its effectiveness arise. For example, growing vegetation such as trees or bushes along the roadside often obscure the visibility of signs from passing vehicles. In addition, substantial intervals exists between speed limit signs on most roads. As a result, vehicle drivers often travel some distance upon a street or road in ignorance of the maximum speed limit thereon.
Despite the best efforts of traffic control practitioners, there arises a continuing and unresolved general need in the art for improvement in the apparatus utilized in communicating traffic control information to vehicle operators. There further arises a particular need in the art for improvements in the apparatus utilized in such communication which supplements and cooperates in conjunction with conventional apparatus of the type presently used to enhance overall safety and control of vehicle operation.